Absci plans Phase 2 STORYLINE trial of ABS-201 for endometriosis
Absci Corporation has released preliminary details of its planned Phase 2 STORYLINE trial evaluating ABS-201, an anti-prolactin receptor (PRLR) antibody designed using the company's generative AI platform, in patients with surgically diagnosed endometriosis and moderate to severe endometriosis-associated pain.
The Nasdaq-listed company, headquartered in Vancouver, Washington, anticipates launching the double-blind, randomised, placebo-controlled study in mid-2027, subject to regulatory clearance and protocol finalisation. The trial will enrol approximately 150 participants across ten or more countries and will assess reductions in dysmenorrhea and non-menstrual pelvic pain using patient-reported outcome measures.
Trial design and dosing strategy
STORYLINE is being designed as a dose-ranging study, with Absci anticipating the testing of two or three dose levels of ABS-201. Final dose selection will be informed by safety, tolerability, and pharmacokinetic data generated in the company's ongoing Phase 1/2a HEADLINE trial, which is evaluating ABS-201 in pattern hair loss. The two indications share the same antibody candidate because PRLR blockade is thought to influence both scalp physiology and endometrial tissue.
Chief Medical Officer Ransi Somaratne said the approach was designed to address a condition that "affects roughly one in ten women of reproductive age, often leading to debilitating and life-altering pain." The company is positioning ABS-201 as a non-hormonal alternative that may offer a "differentiated safety and tolerability profile," though no efficacy data from any endometriosis cohort has yet been released.
Market context and competitive landscape
Endometriosis remains a high-priority area for drug developers. Approved hormonal therapies, including GnRH agonists and combined oral contraceptives, carry tolerability concerns around bone density loss, mood effects, and contraceptive suppression. Two selective progesterone receptor modulators and at least one GnRH antagonist combination have reached the market in recent years, broadening the non-agonist options. The non-hormonal space, where Absci is positioning ABS-201, is less crowded, though a number of early-stage programmes targeting inflammation and neurological pain pathways are in development across academic and commercial settings.
The PRLR target is not widely pursued in endometriosis, which gives Absci a degree of mechanistic differentiation, though clinical validation remains the key outstanding question. Investors will want to see that HEADLINE generates a clean tolerability profile before STORYLINE enrols, given that dose selection is contingent on those data.
The broader AI-designed biologics space is growing rapidly, with several companies using generative models to accelerate antibody discovery and optimisation. Absci's integrated platform, which combines AI design with wet-lab validation in a continuous feedback loop, is one of a handful of such systems now producing clinical-stage candidates. Whether the approach confers a meaningful advantage in efficacy or development speed relative to traditional antibody engineering remains to be demonstrated in late-stage data.
Absci has not disclosed a projected timeline for Phase 3 initiation or any commercial partnership associated with ABS-201 in endometriosis. Near-term milestones to watch include HEADLINE safety and PK readouts, protocol finalisation for STORYLINE, and confirmation of the participating country list ahead of the anticipated mid-2027 start.